Sr20det build question.. Need help with injector size

[White-s13]

Ok so im building my sr and im almost done but i am stuck on injectors... im going to be running the ISIS RS3871r turbo but i have no idea what injectors to run. i was going to use the DW 550cc's but iv been reading they top out at like 350hp.. and i have no idea what my setup will make.. I seen that five-0 has some 750cc's for like $340.. Does anyone use these? I talked to RS-enthulpy and they said that they run rich in boost and lean out of boost. If someone runs these or knows about them and has some advise for me that would be great.

[rc1honda]

Ok so im building my sr and im almost done but i am stuck on injectors... im going to be running the ISIS RS3871r turbo but i have no idea what injectors to run. i was going to use the DW 550cc's but iv been reading they top out at like 350hp.. and i have no idea what my setup will make.. I seen that five-0 has some 750cc's for like $340.. Does anyone use these? I talked to RS-enthulpy and they said that they run rich in boost and lean out of boost. If someone runs these or knows about them and has some advise for me that would be great.

Well I am not sure the size turbo of ISIS turbo but a 3871 sounds like a pretty big turbo. 550cc would be way to small unless you keep it as a low boost setup. 740's should handle most of your power needs, but again seems a little small for a turbo that sounds like could kick out 500hp. When it came to my fuel system I went overkill. I went with SARD 850cc side feeds.

740's or bigger. Just know what kind of injector will work with your setup. Top Feed or side feed? Low impedance or high impedance? Running a SR standalone ECU will usually mean a high impedance (or saturated) injector.

Most injectors go to low impedance after 740cc. SARD and Power Enterprise both have larger high impedance injectors.

Also once you get above 850's most injectors are top feed which means you need a top feed fuel rail. I am sure there are companies the sell large high impedance side feeds that will work with the stock SR rail I am just not sure which ones besides SARD and PE and RC engineering.

So just make sure they fit all your neede criteria for you power goals and fuel setup.

[White-s13]

The ISIS rs3871r is the same a the gr2871r. I am keeping side feed. I think I might go with DW 810cc's. They should be plenty big enough

[codyace]

Crank HP/2/4 = roughly the injector requirment (in lbs) that you need

375whp x1.18 (rough drivetrain loss) = 443 crank. 443/2 = 221.5 221.5/4 = 55.375lb requirement at WOT (so * that number by 10.2 for cc, and you get 565cc requirement for 100 duty at WOT.


So you need to understand what sort of power you are going to make. If you are diehard stuck on sidefeed, i'd get 615's from someplace. I'm not a big fan of the redrilled injectors...not worth the risk IMO.

[White-s13]

Is there a good company that makes 615s? I'm new to the whole fuel and tuning aspect of building motors. I was just gonna get the dw 810s and call it a day that way I don't get too small of ones and be limited to what I can make.

[rc1honda]

Is there a good company that makes 615s? I'm new to the whole fuel and tuning aspect of building motors. I was just gonna get the dw 810s and call it a day that way I don't get too small of ones and be limited to what I can make.

I think you should get some sidefeed 740's and call it a day. Go with tomei or RC engineering all day. As cody was nice enough to calculate for you 565's would do the trick for about 375hp. Only thing is you don't wanna run at 100% duty cycle so hence the 615 recommendation.

With 740's you will have a lot of wiggle room with the tune. If you ever wanted a bigger turbo or more boost, the fuel will be there when you need it. 810 are pretty big and will work too. I just think the 740's will be perfect for your setup.

[240life]

I run DW 740cc's, but there site is now listing 810's..mine all came with a flow chart and have had them for 4 years with no issues.

[White-s13]

I'm gonna go with the dw 740cc's but I can find them for a decent price. I see people get them for under 400. Iv searched my a** off for weeks now and I can't seem to find any. Does anyone know of a site that has them for a good price?